1. Technical Field
The present invention relates to a device for the protection of a person traveling in a vehicle. In particular, the invention relates to a protective element that is fitted to the inside of the roof of a motor vehicle in order to prevent head and neck injuries to a person traveling in the vehicle in the case of certain types of accidents.
2. Prior Art
Many different arrangement are used in modern motor vehicles, such as automobiles, in order to protect the drivers and passengers in the event of a collision and other types of accidents. In addition to safety belts and air bags, which are based on well-tested technology, some more sophisticated systems have been developed in recent years, such as side air bags, to protect the driver and passengers in the event of lateral collisions.
Certain accidents involve a risk of persons in the vehicle hitting their heads on the inside of the roof. One example of such accidents is when the car overturns. Another example is when a vehicle traveling at high speed hits something on the road that protrudes a relatively great distance from the road surface or when the vehicle veers off into a ditch, for example. The result of this may be that the persons traveling in the vehicle hit their heads either on the inside of the roof or on the side portions of the roof frame, which are normally connected to the roof and run basically parallel to the longitudinal axis of the vehicle. In a bad accident, this can cause serious injuries to the head, neck or shoulder of the persons traveling in the vehicle. The situation is the same in the case of certain types of injuries sustained when diving into water, where severe head and neck injuries can occur from hitting a hard object below the surface of the water.
It is a known protective measure to provide an inflatable air bag that is arranged on the inside of the roof of the vehicle. This device is fitted for damping the force with which a person""s head hits the inside of the roof. This device can reduce the risk of head and neck injuries to drivers and passengers. However, it should be pointed out that this device is a rather bulky and expensive solution.
The aim of the present invention is to provide an improved device for the protection of persons traveling in a vehicle in the event of an accident in which they hit their heads on the inside of the roof of the vehicle.
The invention relates to a method and device for the protection of persons traveling in a vehicle. In the structural embodiment, the device is fitted to the inside of the roof of the vehicle. The invention is characterized in that the part of the roof that is expected to come into contact with a person""s head during an accident is equipped with an inner root structure that guides the head in such a way that a bending (flexion) of the neck is initiated essentially simultaneously with the impact between the head and the inside of the roof during the accident.
The invention is based on the fact that, according to recent medical experience relating to diving and ice hockey accidents, the effect of a compressive force against the vertex or crown of the head and acting axially on the head and through the neck, is less likely to cause serious injury in such an impact if the neck is bent at the same time. More specifically, it can be stated that the degree of neck injury depends on several factors including: the angle of impact, the distance from the vertex of the head (i.e., the point on the head where an imaginary extension of the neck would intersect the head), and the properties of the material where the impact takes place. It can be stated that the injury occurs most frequently and is most serious when the impact is basically vertical to the vertex of the head. It can also be stated that a compressive force acting on the head that results in the flexion of the head and neck gives the lowest frequency of neck injuries. It can therefore be concluded that a combined flexion and compression exerted on the head produce considerably less damage than a compressive force acting alone. In addition, in the case of such a combined flexion and compression, the neck absorbs more energy before damage occurs than in the case when only a compressive force is acting.
The aim of the invention is to provide a means or mechanism for guiding a person""s head during an accident in such a way that a flexion of the neck is initiated essentially simultaneously with an axial impact between the head and the inside of the roof of the vehicle. According to the invention, the flexion of the neck is mainly initiated forwards (in relation to the longitudinal direction of the vehicle) or sideways.
The invention provides several advantages. First of all, it considerably reduces the risk of serious head or neck injuries to persons traveling in a vehicle. More specifically, it significantly reduces the neck component of the force measured at the occipital point, where the base of the skull is joined to the uppermost cervical vertebra. This in turn reduces the risk of serious head and neck injuries.
In a preferred embodiment of the present invention, the inside of the roof is fitted with a first layer of material, which is essentially rigid, and a second layer of material, which absorbs energy, as a result of which a flexion of the person""s neck is initiated during an impact involving the head. The fact that the second layer of material absorbs energy has the advantage that it can absorb a large part of the energy that is released when a person""s head hits the roof.